Walnut2 for Thunderbird, based on icons from art.gnome.org. Walnut2 is based on Walnut but with better looking wood panels. Supports Thunderbird versions 53.0 to 60.0. From version 61.0, Thunderbird will drop support for full custom themes.

Walnut for Thunderbird, based on icons from art.gnome.org, and sporting a wooden look.Supports Thunderbird versions 53.0 to 60.0. From version 61.0, Thunderbird will drop support for full custom themes.

Nautipolis for Thunderbird: High-quality, solid theme based on icons from art.gnome.org. Supports Thunderbird versions 53.0 to 60.0. From version 61.0, Thunderbird will drop support for full custom themes.